This invention relates to a fuel supplying device for a vessel propulsion unit and more particularly to an improved and simplified fuel supplying device for an internal combustion engine.
It is well known that an internal combustion engine normally employs a charge forming device for forming a fuel/air charge for operation of the engine and a fuel tank from which fuel is supplied to the charge forming device. Normally some form of pump is required in order to cause the fuel to flow through the system from the fuel tank to the charge forming device. The provision of separate fuel pumps in the conduit interconnecting the fuel tank with the charge forming device has certain disadvantages. When the fuel pump is externally positioned, there must be connections between the fuel pump inlet and outlet and the conduit. These connections give rise to problems on assembly and can become a source of leaks. Therefore, it has been a practice to employ a submersible pump in the fuel tank for delivering the fuel from the tank to the charge forming device. Such arrangements have significant advantages.
There are, however, many applications in which a submerged fuel pump in the fuel tank is not an acceptable alternative. For example, in connection with marine propulsion units and particularly outboard motors, it is normally the practice to provide a fuel tank that is remote from the engine and which is designed to be contained within the hull of the watercraft. Fuel is supplied from this tank to the charge forming device of the power head of the outboard motor through a conduit. If the fuel pump is contained within the fuel tank, this means that electrical power may have to be supplied from the engine to the remotely positioned fuel tank and, furthermore, it also means that a given fuel tank and engine must always be used together. That is, the provision of the fuel pump in the fuel tank requires that the engine that is used with the fuel tank be designed so as to accept such a remotely positioned fuel pump. Also, if the engine is designed to be used with a remotely positioned fuel tank in which the fuel pump is provided, it cannot be readily used on another watercraft that does not have a fuel tank with a fuel pump in it.
It is, therefore, a principal object of this invention to provide an improved fuel supplying device for a vessel propulsion unit.
It is a further object of this invention to provide an improved arrangement for supplying fuel to the charge forming device of an internal combustion engine from a remote fuel tank.
It is a still further object of this invention to provide an improved arrangement wherein a submersible pump can be used in the fuel supply system for an internal combustion engine but need not be submerged in the fuel tank of the engine.
The requirement for compact constructions in outboard motors is well known. If it is desired to provide a fuel pump in the outboard motor, in addition to the aforenoted problems of possible leakage and the use of external connections, the separate fuel pump adds to the spacial requirements of the components of the engine.
It is, therefore, a still further object of this invention to provide an improved and compact fuel pump arrangement for an internal combustion engine such as an outboard motor.